SOLUTION!!!!
With todays computer systems this could be the way forward. You are given a squawk - and the computer tracks for how long you keep the sqauwk (certain ones for RIS/RAS/FIS)
Then you get a bill in the post for the service you received and it will work out how long/distance etc
ONE DAY I WILL BE CHIEF EXEC AND YOU WILL ALL BE IN TROUBLE!!
P.S. "Language Timothy!!!" - been waiting for years to say that mate.
Let's not divert from the main thread fella!!